This invention relates to certain triazolopyrimidine compounds, a process for their preparation, compositions containing such compounds, a method for combating a fungus at a locus comprising treating the locus with such compounds and their use as fungicides.
EP-A-0071792 discloses compounds of formula I ##STR2## in which R.sup.1 represents alkyl, halogen, alkoxy, cyano, cycloalkyl, aryl, aryloxy, arylthio, aralkyl, arylthio, arylalkyl, arylalkyloxy or arylalkylthio each optionally substituted by halogen or alkoxy; or (R.sup.1).sub.n represents a benzene, indane or tetrahydronaphthalene ring fused with the phenyl ring, aromatic moieties in the above groups being optionally substituted by alkyl, alkoxy, halogen or cyano; n is 1 or 2; R.sup.2 and R.sup.3 are each hydrogen, alkyl or aryl, A represents a nitrogen atom or a CR.sup.4 group, and R.sup.4 is as R.sup.2 but can also be halogen, cyano or alkoxycarbonyl or together with R.sup.3 can form an alkylene chain containing up to two double bonds. The compounds are said to be active against various phytopathogenic fungi, especially those of the phycomycete class. However evidence of fungicidal activity is only provided for these compounds against Plasmopara viticola, a member of the oomycete class of fungi.
EP 550113-A2 discloses compounds of the general formula ##STR3## in which R.sup.1 represents an optionally substituted alkyl, alkenyl, alkadienyl, cycloalkyl, bicycloalkyl or 2 heterocyclyl group; R.sup.2 represents a hydrogen atom or an alkyl group; or R.sup.1 and R.sup.2 together with the interjacent nitrogen atom represent an optionally substituted heterocyclic ring; R.sup.3 represents an optionally substituted aryl group; and R.sup.4 represents a hydrogen or halogen atom or a group --NR.sup.5 R.sup.6 where R.sup.5 represents a hydrogen atom or an amino, alkyl, cycloalkyl or bicycloalkyl group and R.sup.6 represents a hydrogen atom or an alkyl group. These compounds are said to be active against fungi which are members of the ascomycetes class such as Venturia inaequalis and of the hyphomycetes class such as Alternaria solani and Botrytis cinerea.